This invention relates generally to devices for brewing and steeping coffee and particularly to a machine which delivers a superior coffee flavor by extracting only the most desirable substances from the coffee grinds. Most coffee brewing machines extract coffee flavorings with steaming hot water. Hot water brewing processes will extract acids along with the coffee flavorings. The acid content is undesirable because it causes a bitter taste and some people may even experience nausea after drinking highly acidic coffee. The present invention reduces the acid content by steeping the grinds in relatively low temperature water. A low temperature steeping process requires a relatively long time to produce a full flavored coffee. The present invention automatically applies the lowest temperature possible to produce a full flavored coffee within a time period selected by the user.
Steaming hot water is commonly used for brewing coffee because heat accelerates the brewing process. There are many hot water processes for brewing coffee. Drip brewing has become the most popular because it is fast and automatic. The drip brewing process drips hot water over coffee grinds, through a filter and into a pot. Despite its popularity the drip brewing process extracts undesirable acids from the grinds because the process uses hot water. Drip machines concentrate the flow of hot water on the central grinds while leaving the periphery grinds relatively unsaturated. Coffee is wasted because the extraction process is incomplete. To overcome this problem some patented coffee makers feature a mechanical agitator to equally expose all the grinds to the brewing process. For the purpose of conserving coffee the cost and complexity of the agitating mechanism is not merited. Drip machines are very tall because the filter basket is located above the pot. They must be dragged out from under the cabinet to pour water into the top. Steam emitted from the top attacks the paint and the wooden structure of the cabinet. The massive size of drip coffee machines makes them unsightly and obtrusive. The most significant drawback of drip machines is that they produce mediocre coffee with a high acid content.
Another popular process of making coffee with hot water is the French method. This process consists of steeping loose coffee grinds in hot water. There are many patented machines for making French coffee. Most are manually operated machines comprising a cylindrical pot and a piston like filter which seals against the walls of the pot. The filter is manually pressed to the bottom of the pot to separate the grinds from the liquid coffee. The French process produces a rich flavored coffee because the grinds are totally saturated in water to gain a complete extraction of coffee flavorings. French brewed coffee is traditionally poured into cups for immediate consumption which is a major reason for the high acclaim given to the fresh taste of French brewed coffee.
A cold steeping process, known as the Dutch method, produces a smooth rich tasting coffee with low acidity. The Dutch method consists of mixing loose coffee grinds in a container of cool water then leaving it to steep for at least 18 hours. The liquid coffee is poured through a filter into a second container in which the coffee is heated on a stove for drinking. While this process produces a very smooth tasting low acid coffee, it is not popular because it is a messy, slow, and totally manual process.
The present invention features a warm steeping process which is basically a combination of the French and Dutch processes. The best tasting coffee is achieved by steeping at a low temperature for a long time. The time required for the warm steeping process can be accommodated by preparing coffee at night for morning consumption. Many drip machines feature a built in timer which permits the machine to be set up at night to produce fresh coffee in the morning, but these machines remain dormant all night only to rush through the drip brewing process in the morning. In this instance the present invention uses all the hours of the night to slowly steep the coffee in warm water. The result is a low acid coffee with superior aroma and smooth taste. A computer controls the water temperature and the sequence of the steeping process. The computer is programmed to automatically heat the water to as low a temperature as possible for producing a full flavored coffee within a time period selected by the user. When the user selects a short steeping time, the computer automatically speeds up the process by using a higher water temperature. When the user selects a long steeping time the computer automatically slows down the processes by using a lower water temperature. The computer is permanently programmed to follow a time and temperature relationship which has been developed by laboratory testing. The present invention is easy to use. To prepare coffee the user loads the proper proportions of water and coffee grinds, sets the timer to the coffee ready time and presses the start button.
Most high quality coffee beans contain less acids than the low quality beans and for this reason high quality beans will produce a relatively low acid coffee even when brewed with a hot water process. The present invention can produce a fine flavored low acid coffee even from low quality beans if enough time is available for a low temperature process. This is a significant cost saving feature because high quality beans generally costs at least twice as much as a low quality beans. The present invention also saves cost by enhancing the extraction process in two ways. Firstly, the grinds are totally immersed in water which exposes all the grinds to the extraction process. Secondly, convection currents are induced by heat applied at the bottom of the pot. The convection currents move the liquid through the coffee grinds to further enhance the extraction process.
The present invention automates the task of making superior tasting coffee. Compared to other types of coffee machines the present invention is convenient, neat and inconspicuous.